#include "Tree.h"
/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param root TreeNode类
     * @return int整型
     */
    int pre(TreeNode* root)
    {
        if (root == NULL) return 0;
        int c = 0;

        if (root->left != NULL && root->left->left == NULL && root->left->right == NULL) c =  root->left->val;

        int a = pre(root->left);
        int b = pre(root->right);

        return a + b + c;
    }

    int sumOfLeftLeaves(TreeNode* root)
    {
        return pre(root);
    }
};